Measuring them along the base, following the curves of the tip and tail:
-1999 Ride Yukon 164,--------measures 0.5cm less
-1999 K2 Luna 157,-----------measures 1.0cm less
-2011 Lib Tech T.Rice 161.5,-measures 0.2cm less

They all measure less than advertised, the Lib Tech being the closest to what's advertised.